High-Resolution and High-Accuracy Fiber-Optic Tilt Sensor and Its Calibration

The inclination angle measurement is crucial in structural safety monitoring. In this article, a high-resolution and high-accuracy fiber-optic tilt sensor based on the Fabry-Perot (F-P) interferometer is proposed. One end of the steel sheet fixed with an F-P filter is connected to a mass block, and the other end is connected to the revolution axis of the pedestal, thus forming a simple pendulum structure. The tilt of the sensor will cause the incident angle of the light to change, which will cause the center wavelength to shift. The structure design and measurement principle of the sensor are given in detail, and the comprehensive performance test of the sensor prototype is carried out. The experimental test results show that the sensor has high sensitivity, good repeatability, and low hysteresis in the range of −3° to 3°, and the measurement resolution can reach 0.0007°. The backpropagation (BP) neural network calibration method is used to make the measurement accuracy of the sensor reach ±0.009°. The tilt sensor designed in this article has the characteristics of simple structure, high accuracy, high resolution, and good stability, which is suitable for tiny angle measurement in small range.